Gate valves are a common linear valve type found in pipelines, both above and below ground. A gate valve is designed to start and stop the flow of liquid through ducting, allowing users to isolate a section of pipe when required. They are often called water gate valves or sluice valves.
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When people ask what is a gate valve, they will often have follow-up requests for more information on what gate valves look like, what parts they include, the differences between various types, and exactly how they work. We will cover all of these areas in the various sections of this guide.
Gate valves usually consist of the valve body itself, which is installed in-line (through-conduit) on a length of pipe, and an attached handwheel actuator used for opening and closing the valve. This multi-turn wheel assembly most often extends above or to the side of the pipe and valve, attached to a bonnet assembly via a stem. It can be turned in one direction to open the valve, and in the opposite direction to close it.
The advantages of a gate valve are that they provide complete shut-off of any water flow for troubleshooting, maintenance and pipe-cleaning tasks. They are also bidirectional, meaning they can be used to block flow in both upstream and downstream directions, and they do not cause significant pressure loss in operation.
Limitations of gate valves in certain scenarios may include the fact that they are not especially quick to open or close. Additionally, they are not designed to throttle or control flow by being partially opened or shut.
This guide is designed to explain in more detail what gate valves are, what they are used for, how they work, and the different types of UK gate valves available to buy online. We will also briefly outline how to use them, as well as providing some clear and concise answers to common questions about gate valves. By the end of the guide, readers will be familiar with what sluice valves are, how they work, and why they are used.
Most types of gate valve can be thought of simply as a sluice valve or control valve for water supply. Gate valves are used for starting or stopping the flow of liquid (or steam/gas) through a section of pipeline, allowing that section to be completely shut off and isolated when necessary.
They are among the most common sorts of valves and taps you will find in most pipeline applications, and are used in a wide range of industrial settings. These might typically include:
Certain types of gate valves are often suitable choices for both high pressure and high temperature applications. Although quite a simple sort of valve in principle, they are highly effective when used in the right circumstances. Being fire-safe also means they are a suitable choice for high pressure-temperature scenarios.
Unlike some other types of shutoff valves (such as globe valves), a gate valve is only intended to be used in its fully open or fully closed state. Leaving it in a partially raised or lowered position will not have much effect on controlling the flow rate of the medium in the pipe, and may risk moving or damaging the valve due to excessive vibration.
Another common type of isolation valve is a ball valve, which is somewhat different from a gate valve in terms of its physical construction. However, both will achieve a similar effect in the sense that they will completely block the flow of water through a duct when fully closed. There are numerous key factors involved in deciding between a ball valve vs. a gate valve for a given pipeline application or industrial setting. These will normally include the sorts of environmental conditions they are being used in, and the properties of the medium where they are controlling the flow.
Gate valves should also be distinguished from check valves, another familiar pipeline device used to control directional flow, and butterfly valves. The main difference between check valves and gate valves is that the former is designed to prevent backflow; they allow unhindered flow in one direction while blocking it in the opposite direction. By contrast, gate valves are bidirectional, and will completely shut off the flow of fluid, vapour or gas in both directions when in a closed position.
A butterfly valve is a variation of a gate or isolation valve. They usually require just a quarter-turn of the valve actuator handle to open or close. The gate itself sits either parallel or perpendicular to the flow direction inside the pipe, depending on the position of the actuation device relative to the valve body. They are generally less suitable than gate valves in situations where achieving a very tight seal is critical, but some versions can be used to throttle.
The two main types of gate valves are wedge-shaped and parallel. Wedge-shaped gate valves (including solid taper wedge, flexible wedge and split wedge designs) use two inclined seats and an inclined gate or barrier, which is intentionally slightly misaligned with the seats. This tends to achieve a tighter seal than a parallel version in certain applications. Parallel gate valves, sometimes called parallel disks, double disks or parallel slide gate valves, have a flat gate or barrier held perpendicular to the flow of liquid between two parallel seats.
There are various sorts of gate valves used in numerous applications across a wide range of pipeline and workplace types. Below, we have listed some of the most popular types of gate valves on sale in the UK and elsewhere, with a brief description of each kind.
A wedge gate valve is one of the more common types you will find in widespread use across all relevant plumbing and industrial pipeline setups. Subtypes include the solid wedge, the flexible wedge, and the split wedge.
Solid wedge gate valves (or plain wedge valves) tend to be the most widely used. They are often among the simplest and cheapest options but offer good mechanical strength. They are broadly suitable for nearly all types of fluid media. Their robust, single-piece construction makes them especially appropriate for use in pipelines with turbulent fluid flow.
In wedge valves, the barrier or gate is slightly inclined against the flow path of pressurised liquid in the pipe. For this reason, they are also referred to as tapered gates. This angle creates a wedging force as the valve closes, and helps to make for a more reliable seal at higher fluid pressure ratings.
A split gate valve, or split wedge gate valve, is a type of wedge valve in which the wedge disk itself is made from two solid pieces, held in place by a spacer or spring. This gives it the ability to self-adjust to the seats, providing added flexibility and making it easier to achieve a tighter seal with less risk of sticking or binding. They are particularly suitable for use with non-condensing gases and corrosive liquids.
A parallel gate valve (sometimes called a parallel disk gate valve, or parallel slide gate valve) operates in much the same way as a wedge gate valve, but the gate features two disks placed at a 90-degree angle to the fluid flow direction. They are generally seen as safer in high temperature applications, where the parallel design is less likely to result in thermal binding.
A knife gate valve is a well-known type that is designed primarily for use with very thick or viscous fluids, such as slurry or powder-carrying liquid. The disks in the knife gate valve model are tapered (effectively sharpened, hence knife valves) at one end to enable them to cut and move through thicker media more easily when closing.
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A flanged gate valve is one where the body of the valve is flanged and bolted to the bonnet (the part on top of the valve through which the handwheel assembly connects, and which gives access to the moving parts of the valve). This tends to make them better suited to higher pressure applications than screwed connections, but less ideal than specialist pressure sealing models.
Gate valves are used to completely stop or start the flow of fluid through a pipeline by lifting or lowering a solid, rectangular gate. These valves consist of a valve body, seat, disc, spindle, gland and actuator.
Gate valves are not used to regulate flow — they are designed to be fully open or fully closed. These valves are slower than quarter-turn valves (like ball valves) because they require more than a 360° turn to change the position of the gate, whereas a ball valve requires only a 90° turn to cycle from open to closed or vice-versa. Because of this, gate valves may not be the best choice for applications that require frequent operation or fast cycle times. Gate valves are most commonly controlled by a manual handwheel, but electric and pneumatic actuation options are also available.
While a solid rectangular gate controls the flow of media through a gate valve, a ball valve relies on a pivoting ball to control the flow of liquid or gas. The ball has a bore (or hole) in it that the media passes through, and its position indicates whether the valve is open or closed.
Ball valves can be designed with multiple openings, also known as ports. Two-way ball valves have two ports and are used for basic on/off control. There are also multi-port valves that are used in applications that need to divert media in different directions or that may require more than one source of media.
Since ball valves only require a 90° turn to control the position of the ball, they are a faster option for on/off control than gate valves. Ball valves are available with manual or automated actuation.
As we mentioned, ball valves operate by rotating a ball 90° while gate valves are controlled by moving a gate up or down. Because of their design, ball valves can perform an almost immediate shutoff, whereas gate valves are not able to act as quickly. This makes ball valves a better choice for applications where fast cycle speed is desired.
The 90° operation of ball valves makes them faster to cycle, both manually and with an actuator. This is a benefit in most instances but can potentially cause water hammer in high-pressure applications. If the pressure is high enough, the pipe could weaken or even break, which is why users of manual ball valves should turn the levers slowly to avoid water hammer.
Gate valves are commonly found in older home plumbing systems.
On/off control for specialized industries including:Ball valves are also found in newer home plumbing systems.
In the gate valve vs. ball valve debate, cost is a major differentiating factor. Up front, gate valves are less expensive than ball valves, but they can be more susceptible to corrosion which means they will need repairs and replacement more frequently. Ball valves have a higher initial cost, but they are the better choice for longevity since they are more durable and highly effective at forming tight seals.
As we just discussed, gate valves are, in general, less durable than ball valves. In moderate or high cycle applications, gate valves will require routine maintenance or replacement. Most ball valves are designed to be maintenance-free and should be replaced rather than repaired. Three-piece ball valves, however, are designed so that the valve seats and seals can be easily replaced without removing the valve from service. This is why 3-piece ball valves are often used in high cycle or high pressure applications where valve seal failure is likely to occur more quickly. However, 3-piece ball valves typically come with a higher up-front cost than the more popular 1-piece or 2-piece body constructions.
Ultimately, the choice between a gate valve and a ball valve will depend on the application. Gate valves are best suited for applications that require infrequent operation and small installation space. Ball valves are ideal for applications that require fast cycle times, multiple ports, reliable, tight seals and/or frequent operation.
Here is a recap of what we’ve covered in this article to further assist your decision:
Ball valves create a reliable, tight seal, so they can be used with both liquids and gases. Gate valves are better suited for thick liquids (like oil) since they are more prone to leaking.
Ball valves are smaller than gate valves, but they require more space for operation. A manual ball valve requires a lever that can turn 90° but a manual gate valve can operate with a small handwheel. Some ball valves are available with small form factor handle options, such as wing or round-style handles. These handles work well with smaller pipe sizes but often do not provide enough leverage for larger ball valves.
Gate valves are recommended for liquid media applications that require infrequent operation. Ball valves are used across a variety of industries that require active, quick control of the flow of media.
Unlike ball valves, gate valves are not widely available in multi-port configurations. If your application requires a multi-port flow pattern, a ball valve may be the right choice.
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Gemini Valve designs, manufactures and distributes performance-engineered ball valves, including custom products. If you have questions about whether a ball valve or gate valve is right for your application, contact us here for more information or to speak with a specialist.
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